Blue sulfur dyestuff and process of making same.



UNITED STATES Patented December 22, 1903.

PATENT OFFICE.

NIKLAUS RONGGER, OF BASLE, SWITZERLAND, ASSIGNOR TO CORPORA- TION OFCHEMICAL WORKS FORMERLY SANDOZ OF BASLE, SWITZER- LAND.

BLUE SULFUR DYESTUFF AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 747,643, dated December22, 1903.

Application filed July 14, 1903. Serial No- 165622. (Specimens) To allwhom it may concern:

Be it known that I, NIKLAUS RONGGER, doctor of philosophy, residing at60 Fabrikstrasse,Basle,Switzerland,have invented new 5 and usefulImprovements in Blue Sulfur Dye,

of which the following is a'specification.

Hitherto the sulfur colors deriving from leuco indophenols have beenprepared in a general way by heating the indophenols or their leucocompounds with alkali polysulfids at temperatures not exceeding, as arule, 120 centigrade. At higher temperatures dyestufis of more blackishblue and duller shade are formed.

: Now I have discovered that the para-oxypara-amidometa-methyl-diphenylamin described in the United States PatentNo.709,151 can be transformed in a very valuable blue sulfur dye bysimply heating it with sulfur at elevated temperatures varying from 170to 210 centigrade. A strong current of sulfureted hydrogen is developedin the reaction, and after two hours the entire process is complete. Themelt can be used directly for z 5 dyeing without any furtherpurification. By

adding to the ingredients of the melt a smallquantity of chromiumhydroxid the shade of the resulting dyestuif becomes a trifle more Ireddish and brighter,the general properties of the product remaining,however, unaltered. The following example will illustrate my inventionand in what manner the same can be carried out into practical efiect.The parts are by weight. 5' Six parts of para-oxy-para-amidometamethyl-diphenylamin,five parts of sulfur, and .2 parts of chromiumhydroxid (Or O,,H O) are heated in an iron vessel provided with anagitator to 190 to 200 centigradetemper- 4.0 atureof the oil-bath. Thereaction sets in very quickly, accompanied by a strong developmentof'sulfureted hydrogen. It slows down toward the end of the process.After two hours stirring the melt, which is at 5 first liquid, becomesthick. It is then cooled down, when a brittle blackish violet mass isobtained, which can be easily powdered and used directly for dyeing.

The dyestuff thus produced is completely insoluble in water, butdissolves readily in presence of alkaline sulfidsviz.,with a blue colorin the cold, and at boiling forming a vat with a slightly-brownishcoloration which dyes unmordanted cotton,preferably at ordinarytemperature, with remarkable affinitywhereas the dyestuff obtained fromthe same diphenylamin derivative according to the United States Patent N0. 709,151 before mentioned produces at first slightly red-brown shades,which oxidize on exposure to the air through reddish violet to blue..The sulfur dye produced according to the present invention turns out ofthe dyeing-kettle slightly grayish green and oxidizes on exposure to theair directly to an intense indigo blue fast to alkalies, washing, andlight.

If the melt of the foregoing example is made without addition ofchromium hydroxid, a dyestuff having the same general properties isobtained,which, however, dyes slightly 7o duller and more greenishshades.

' In order to isolate the dyestuff in a pure state from the melt, thesolution of the latter in diluted sodium sulfid can be precipitated byoxidation with a current of air, or the leuco compound may be separatedby addition of a mineral acid, filtered, washed, and dried, andafterward freed from the sulfur still contained therein by extractionwith carbon disulfid. On exposure to the air the dyestuff is obtained asa dark blue powder, insoluble in water and alcohol, soluble'in coldsulfuric acid with a blue color, which turns to gray on heating. Itdissolves very easily in diluted alkaline sulfids with a blue color inthe cold, which is discolored to a slight brown on boiling.

Now what I claim, and desire to secure by Letters Patent, is thefollowing:

1. The process herein described for the 0 manufacture of a blue sulfurdyestuff which consists in heatingpara-oxy-para-amido-metamethyl-diphenylainin with sulfur to to 210centigrade.

2. The process herein described for the 5 manufacture of a blue sulfurdyestuff which consists in heatingpara-oxy-para-amido-metamethyl-diphenylamin with sulfur to 170 to 210centigrade in the presence of chromium hydroxid. I00

3. As a new article of manufacture, the dyestuff herein describedobtained from pareoxy-para-amido-metamethyl-diphenylamin, being a darkblue powder, insoluble in water and alcohol, easily soluble in colddiluted a1- kaline sulfids with a. blue color which is changed to aslight brown on boiling, dissolving in cold strong sulfuric acid withblue color and dyeing nnmordanted cotton in a.

bath containing alkaline sulfide blue shades 1o fast to alkalies,washing and light.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

NIKLAUS RONGGER.

Witnesses:

GEO. GIFFORD, MELCHIOR BdNIGER.

